In the past, wax patterns have been fabricated by the addition of small increments of molten wax to the main body of the pattern. In the construction of dental bridge work, inlays and crowns, for example, a dental instrument is heated over a flame and then touched to a bulk supply of wax. The molten wax thus deposited on the end of the instrument then is transported to, and placed on, the embryonic pattern. Building up a pattern in this manner is repetitive, tedious and enormously time consuming.
It has been proposed (Schoelz U.S. Pat. No. 3,522,654) to meet this problem by the provision of a pen-like waxing tool in which molten wax contained in a reservoir is discharged onto the wax pattern through a nozzle, continuously or incrementally. However, in the execution of this technique a serious and often fatal problem is presented by the fact that molten wax has the curious and unique property of seeping through flow control valves fabricated from metal, glass or ceramic parts, This is believed to be a surface tension phenomenon. Molten wax at atmospheric pressure will leak through a valve fabricated from metal components which is impervious to water at 50,000 psi. This property of molten wax destroys the utility of the implement, since it is impossible to control the flow of molten wax accurately.
It is the general purpose of the present invention to provide a molten wax applicator which is impervious to the flow of wax and leak proof when the applicator is in its closed or turned off mode.
It is a further important object of the present invention to provide a molten wax dispenser which is convenient to hold and operate and which has the capability of delivering molten wax drop-wise or continuously on demand, but which is leak-proof when not in use.
Further objects of the present invention are the provision of such an applicator in which the temperature of the molten wax can be controlled accurately, in which the quantity of molten wax dispensed can be controlled accurately, which compensates for expansion and contraction of associated valving components, which will withstand high temperatures, which is adaptable to the dispensing of molten wax in large or small amounts, which can be easily assembled, cleaned and serviced; and which is easily loaded with the feed wax.
It is still a further object of the invention to provide a molten wax applicator having a hot nozzle through which the wax is dispensed. The hot nozzle melts the surface of the embryonic pattern, ensuring complete fusion of the newly added wax increment to the pattern.